New ride (87 300D), 5 speed swap and suspension questions
 

After buying my 190D almost 5 years ago and having no major problems with it, I have really fallen in love with Mercedes diesels. I have been looking for a W124 diesel car for a couple of years and finally found an 87 300D in NC for 2500 bucks. It has not quite 170k miles on it. It has the original paint, only 1 small spot of paint bubbling on the rear quarter panel, and faded paint on the roof. Interior is nearly perfect and everything works except for cruise and AC. It has had only 3 owners according to Carfax (all in NC), and is pretty much unmolested as far as wiring, engine compartment, etc. goes.

When I brought it home, it would not get over 85 mph. I already had some fuel filters for it, so I changed those out. The primary filter looked like it had never been changed. After that, it would pull hard to 100 mph and still be accelerating. Not sure if it would hit the advertise top speed of 128, but I was happy with it. As a bonus, the transmission started shifting much better since I was giving less throttle input for the power.

I still did not like how dead the throttle felt at the low end, so I removed the ALDA. It is like a whole new car now. Amazingly, it does not smoke at all on takeoff as long as I drive normally and even flooring it only puts out a small puff of smoke.

It has a small, intermittent coolant leak from what looks like an auxiliary water pump before the heater core. Is this a common problem or a failure waiting to happen? The car still has a #14 head on it, but has a new radiator and fan clutch and never gets over 90C, but obviously losing large amounts of coolant isn't going to help that head last.

I also won a set of 98 CLK wheels on ebay a couple of days ago with tires on them for 400 bucks shipped which I thought was a pretty good deal. I just need to get some lug bolts and they should bolt on, right?

When I accelerate hard, the rear of the car pulls hard to the right and then pulls hard to the left when I decelerate. It also clunks a bit sometimes when it shifts. I got underneath it tonight and it looks like there are a few bushings that are questionable. One of the bushings supporting the rear of the diff. housing is junk and I can move the housing about 1/4" each way. Hopefully this is the source of the clunk. I looked on Fastlane and it appears that what I need is the rear differential mount to subframe bushings, is this correct?

There is also some well worn bushings on what I think is called the thrust arm. I do not see seperate bushings for this, so I assume you have to buy the whole arm. Would this cause the pull I feel?

First tank I got 29.2 mpg. Seems a little bit low since the EGR is now disabled and it has new fuel filters. We will see how the next tank does.

One last thing, the 190D is getting very rusted, and eventually it will not be road worthy anymore. I would like to pull the transmission out of it and put it in the 300D someday. It sounds like the pedal assembly is the same which will make things much easier. It also sounds like the trans will bolt right in, but the flywheel may not work as well as the shift linkage. The flex joints on the 190 I think are a lot smaller, so maybe I need to get a larger output for the trans. The 190 is a gray market car if it makes any difference. Any advice about this swap would be greatly appreciated. Here are some pics of the car in case anyone is interested:

dang.you.cat...

yes they will work. BUT! you need to use SUPER SHORT lug bolts on the rear. if you don't, you will jack up your e-brake.

29 mpg is about right.

Your mileage is about right, the only way you'll break 30mpg is a long trip at 55-60 with all the right fluids, clean air filter, etc., you might see 32-33.

The thrust-link will cause it to pull under accel/decel.

Not sure about the transmission swap, that's a 4cyl so it has the smaller clutch, and you'll need a flywheel. I was considering the same with an '87 (5cyl) donor, but decided that I prefer the automatic, sold the 5-speed donor.